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/** @file
Functions and types shared by the SMM accessor PEI and DXE modules.
Copyright (C) 2015, Red Hat, Inc.
Copyright (c) 2024 Intel Corporation.
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
#include <IndustryStandard/Q35MchIch9.h>
#include <Library/DebugLib.h>
#include <Library/PcdLib.h>
#include <Library/PciLib.h>
#include "SmramInternal.h"
//
// The value of PcdQ35TsegMbytes is saved into this variable at module startup.
//
UINT16 mQ35TsegMbytes;
//
// The value of PcdQ35SmramAtDefaultSmbase is saved into this variable at
// module startup.
//
STATIC BOOLEAN mQ35SmramAtDefaultSmbase;
/**
Save PcdQ35TsegMbytes into mQ35TsegMbytes.
**/
VOID
InitQ35TsegMbytes (
VOID
)
{
mQ35TsegMbytes = PcdGet16 (PcdQ35TsegMbytes);
}
/**
Save PcdQ35SmramAtDefaultSmbase into mQ35SmramAtDefaultSmbase.
**/
VOID
InitQ35SmramAtDefaultSmbase (
VOID
)
{
mQ35SmramAtDefaultSmbase = PcdGetBool (PcdQ35SmramAtDefaultSmbase);
}
/**
Read the MCH_SMRAM and ESMRAMC registers, and update the LockState and
OpenState fields in the PEI_SMM_ACCESS_PPI / EFI_SMM_ACCESS2_PROTOCOL object,
from the D_LCK and T_EN bits.
PEI_SMM_ACCESS_PPI and EFI_SMM_ACCESS2_PROTOCOL member functions can rely on
the LockState and OpenState fields being up-to-date on entry, and they need
to restore the same invariant on exit, if they touch the bits in question.
@param[out] LockState Reflects the D_LCK bit on output; TRUE iff SMRAM is
locked.
@param[out] OpenState Reflects the inverse of the T_EN bit on output; TRUE
iff SMRAM is open.
**/
VOID
GetStates (
OUT BOOLEAN *LockState,
OUT BOOLEAN *OpenState
)
{
UINT8 SmramVal, EsmramcVal;
SmramVal = PciRead8 (DRAMC_REGISTER_Q35 (MCH_SMRAM));
EsmramcVal = PciRead8 (DRAMC_REGISTER_Q35 (MCH_ESMRAMC));
*LockState = !!(SmramVal & MCH_SMRAM_D_LCK);
*OpenState = !(EsmramcVal & MCH_ESMRAMC_T_EN);
}
//
// The functions below follow the PEI_SMM_ACCESS_PPI and
// EFI_SMM_ACCESS2_PROTOCOL member declarations. The PeiServices and This
// pointers are removed (TSEG doesn't depend on them), and so is the
// DescriptorIndex parameter (TSEG doesn't support range-wise locking).
//
// The LockState and OpenState members that are common to both
// PEI_SMM_ACCESS_PPI and EFI_SMM_ACCESS2_PROTOCOL are taken and updated in
// isolation from the rest of the (non-shared) members.
//
EFI_STATUS
SmramAccessOpen (
OUT BOOLEAN *LockState,
OUT BOOLEAN *OpenState
)
{
//
// Open TSEG by clearing T_EN.
//
PciAnd8 (
DRAMC_REGISTER_Q35 (MCH_ESMRAMC),
(UINT8)((~(UINT32)MCH_ESMRAMC_T_EN) & 0xff)
);
GetStates (LockState, OpenState);
if (!*OpenState) {
return EFI_DEVICE_ERROR;
}
return EFI_SUCCESS;
}
EFI_STATUS
SmramAccessClose (
OUT BOOLEAN *LockState,
OUT BOOLEAN *OpenState
)
{
//
// Close TSEG by setting T_EN.
//
PciOr8 (DRAMC_REGISTER_Q35 (MCH_ESMRAMC), MCH_ESMRAMC_T_EN);
GetStates (LockState, OpenState);
if (*OpenState) {
return EFI_DEVICE_ERROR;
}
return EFI_SUCCESS;
}
EFI_STATUS
SmramAccessLock (
OUT BOOLEAN *LockState,
IN OUT BOOLEAN *OpenState
)
{
if (*OpenState) {
return EFI_DEVICE_ERROR;
}
//
// Close & lock TSEG by setting T_EN and D_LCK.
//
PciOr8 (DRAMC_REGISTER_Q35 (MCH_ESMRAMC), MCH_ESMRAMC_T_EN);
PciOr8 (DRAMC_REGISTER_Q35 (MCH_SMRAM), MCH_SMRAM_D_LCK);
//
// Close & lock the SMRAM at the default SMBASE, if it exists.
//
if (mQ35SmramAtDefaultSmbase) {
PciWrite8 (
DRAMC_REGISTER_Q35 (MCH_DEFAULT_SMBASE_CTL),
MCH_DEFAULT_SMBASE_LCK
);
}
GetStates (LockState, OpenState);
if (*OpenState || !*LockState) {
return EFI_DEVICE_ERROR;
}
return EFI_SUCCESS;
}
EFI_STATUS
SmramAccessGetCapabilities (
IN OUT UINTN *SmramMapSize,
IN OUT EFI_SMRAM_DESCRIPTOR *SmramMap
)
{
UINTN BufferSize;
EFI_HOB_GUID_TYPE *GuidHob;
EFI_SMRAM_HOB_DESCRIPTOR_BLOCK *DescriptorBlock;
UINTN Index;
//
// Get Hob list
//
GuidHob = GetFirstGuidHob (&gEfiSmmSmramMemoryGuid);
DescriptorBlock = GET_GUID_HOB_DATA (GuidHob);
ASSERT (DescriptorBlock);
BufferSize = DescriptorBlock->NumberOfSmmReservedRegions * sizeof (EFI_SMRAM_DESCRIPTOR);
if (*SmramMapSize < BufferSize) {
*SmramMapSize = BufferSize;
return EFI_BUFFER_TOO_SMALL;
}
//
// Update SmramMapSize to real return SMRAM map size
//
*SmramMapSize = BufferSize;
//
// Use the hob to publish SMRAM capabilities
//
for (Index = 0; Index < DescriptorBlock->NumberOfSmmReservedRegions; Index++) {
SmramMap[Index].PhysicalStart = DescriptorBlock->Descriptor[Index].PhysicalStart;
SmramMap[Index].CpuStart = DescriptorBlock->Descriptor[Index].CpuStart;
SmramMap[Index].PhysicalSize = DescriptorBlock->Descriptor[Index].PhysicalSize;
SmramMap[Index].RegionState = DescriptorBlock->Descriptor[Index].RegionState;
}
return EFI_SUCCESS;
}
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